Background Cytokine-mediated immunity plays a crucial role in the pathogenesis of various autoimmune diseases including systemic lupus erythematosus (SLE). The aim of this study was to evaluate association between serum levels of IL-23 and vascular involvement in SLE patients.

Materials and methods Study was performed in 94 SLE patients (82 women and 12 men) aged 19–73 years and in 27 age and gender matched controls. Serum IL-23 was measured with ELISA method using R and D Systems tests.

Carotid intima-media thickness and the presence of atherosclerotic plaques in carotid and lower extremities arteries were analysed with B-mode ultrasound. Ankle-brachial and high resistance indexes were measured with Doppler ultrasonography.

We took into account classical cardiovascular risk factors (hypertension, dyslipidemia, hyperglycemia, overweight/obesity, smoking, oral contraceptives, positive family history of cardiovascular disease), selected clinical manifestations (cardiovascular, cerebrovascular, lupus nephritis, Raynaud’s phenomenon, livedo reticularis, vasculitis, other thromboembolic complications), profile of autoantibodies (antinuclear, antiphospholipid, anti-neutrophil cytoplasmic, anti-endothelial cell).

Statistical analysis was performed with: chi ²Yates, chi ²Pearson, rank Spearman correlations tests, logistic regression analysis and multivariate stepwise analysis.

Results Concentrations of IL-23 significantly differed between SLE patients and the controls (p=0.0005). Patients with high levels of IL-23 more frequently developed atherosclerosis showed as the presence of plaques in right common femoral artery (OR=10.1; 95% CI:1.2–85.1) and lupus nephritis (OR=3.2; 95% CI:1.1–9.6). Among classical atherosclerotic risk factors only obesity was significantly associated with IL-23 (OR=3.8; 95% CI:1.2–12.3). Immunological characteristics significantly related to IL-23 were anti-phosphatidylethanolamine antibodies (OR=12.7; 95% CI:1.5–108.1) and anti-SS-B antibodies (OR=11.8; 95% CI:1.5–94.8). Association with anti-cardiolipin and anti-prothrombin antibodies was on the border of statistical significance (OR=2.3; 95% CI:0.9–5.7 and OR=8.4; 95% CI:1.0–71.1 respectively).

Conclusions

1. IL-23 may be involved in lupus nephritis pathogenesis. 2. IL-23 through its significant association with obesity and antiphospholipid antibodies may promote hypercoagulable state contributing to atherothrombosis development in SLE patients.